Re: [Bug 111441] New: iscsi fails to attach to targets

[Mike Christie <michaelc@cs.wisc.edu>]

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On 02/02/2016 12:09 PM, Christoph Hellwig wrote:
> On Fri, Jan 29, 2016 at 05:32:54PM -0600, Mike Christie wrote:
>> Hey Christoph and Hannes,
>>
>> The dh/alua changes that added this:
>>
>>         error = scsi_dh_add_device(sdev);
>>         if (error) {
>>                 sdev_printk(KERN_INFO, sdev,
>>                                 "failed to add device handler: %d\n",
>> error);
>>                 return error;
>>         }
>>
>> to scsi_sysfs_add_sdev are adding a regression.
>>
>> 1. If that fails, then we forget to do device_del before doing the
>> return. My patch in this thread added that back, so we do not see the
>> sysfs oopses anymore. But.....
> 
> Ok.
> 
>> 2. It looks like in older kernels, we would allow misconfigured targets
>> like this one to still setup devices. Do we want that old behavior back?
>> Should we just ignore the return value from scsi_dh_add_device above?
>> Note that in this case, it is LIO so it can be easily fixed on the
>> target side by just setting it up properly. I do not think other targets
>> would hit this type of issue.
> 
> Be liberal in what you accept..  I guess we need to continue allowing
> to connect to these broken targets, but a warning would be useful.
> 
> Can you send a patch?

Serguei, can you try the attached patch? Drop the other one I sent.

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diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index 21930c9..7dcc4bf 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -1059,9 +1059,12 @@ int scsi_sysfs_add_sdev(struct scsi_device *sdev)
 
 	error = scsi_dh_add_device(sdev);
 	if (error) {
+		/*
+		 * Allow device setup to succeed. Attachment can be retried
+		 * from userpsace or device can be still used in degraded mode.
+		 */
 		sdev_printk(KERN_INFO, sdev,
 				"failed to add device handler: %d\n", error);
-		return error;
 	}
 
 	device_enable_async_suspend(&sdev->sdev_dev);